Sizing composition

ABSTRACT

The present invention relates to sizing of paper and more specifically to a substantially water-free and aqueous composition of a sizing agent where the composition contains a cellulose reactive sizing agent, a cationic compound with a molecular weight up to 10000 and a non-ionic compound. Additionally, the invention relates to the preparation and use of above-mentioned compositions.

This application is a 371 of PCT/SE00/00622 filed Mar 30, 2000 whichclaims benefit of Provisional Application Ser. No. 60,129,410 filed Apr.15, 1999.

The present invention relates to sizing of paper and more specificallyto substantially water-free compositions and aqueous compositions ofcellulose-reactive sizing agents, their preparation and use.

BACKGROUND

Cellulose-reactive sizing agents, such as those based on alkyl ketenedimer (AKD) and alkenyl succinic anhydride (ASA), are widely used inpapermaking at neutral or slightly alkaline stock pH's in order to givepaper and paper board some degree of resistance to wetting andpenetration by aqueous liquids. Paper sizes based on cellulose-reactivesizing agents are generally provided in the form of dispersionscontaining an aqueous phase and finely divided particles or droplets ofthe sizing agent dispersed therein. The dispersions are usually preparedwith the aid of dispersing agents consisting of an anionic compound,e.g. sodium lignosulfonate, preferably in combination with a highmolecular weight amphoteric or cationic polymer, e.g. cationic starch,polyamine, polyamideamine or a vinyl addition polymer. However,dispersions of these types usually exhibit rather poor stability andhigh viscosity, even at relatively low solids contents, which evidentlylead to difficulties in handling the dispersions, for example on storageand in use. A further drawback is that the products have to be suppliedas low concentration dispersions which further increases the costs oftransportation of the active sizing agent as well as the cost forstorage due to the large volume occupied by the aqueous content ofcommon dispersions.

U.S. Pat. No. 5,176,748 refers to a sizing composition containing ASA, acationic soluble dispersing agent and optionally a non-ionic surfactant.The cationic dispersing agents used are high molecular cationicdispersing agent such as diallyl dimethyl ammonium chloride (Polydadmac)having molecular weights of around 50,000.

EP 220941 A1 relates to a solid composition comprising ketene dimers, anencapsulating agent such as polyethers and a cationic polymer such aspolyamines.

U.S. Pat. No. 4,743,303 discloses aqueous dispersions of rosin andsynthetic sizing agents comprising non-ionic surface active agents andcationic dispersing agents.

EP 707110 A1 relates to an alkenylsuccinic emulsion sizing agentcomprising an emulsifier and/or an anionic high-molecular weightstabiliser.

Before usage of the compositions they are emulsified in the presence ofan aqueous phase. In order to reduce the particle size shear forces arerequired. One advantage of the present invention is therefore to improveemulsification/dispersing properties. Yet another advantage of thepresent invention is to achieve good and/or improved sizing while usinga substantially water-free sizing composition which disperses easy/fastin an aqueous phase. Furthermore the problem of stability relating tothe usual sizing dispersions is circumvented by providing a sizingcomposition which is essentially water-free. Further objects will appearhereinafter.

The Invention

In accordance with the present invention it has been found that improvedhomogenisation can be obtained with an essentially water-freecomposition according to the claims. More specifically, the inventionrelates to an essentially water-free composition of a cellulose-reactivesizing agent comprising a non-ionic compound and a cationic compoundwith a molecular weight of up to 10,000 which are effective asdispersing agents. The size compositions of this invention are easilyhomogenised thus minimising the use of shear forces. In addition, thepresent invention relates to an aqueous composition of acellulose-reactive sizing agent and their preparation and use, asfurther defined in the claims.

The present composition makes it possible to reduce transportation costsby virtually excluding the amount of water usually present indispersion. The present invention thus offers substantial economic andtechnical benefits.

By aqueous composition is also meant an aqueous dispersion of acellulose reactive sizing agent. Accordingly, an aqueous dispersion oran aqueous composition is obtained by emulsification or homogenisationof the substantially water-free composition of a sizing agent.

The cellulose-reactive sizing agent according to the invention can beselected from any of the cellulose-reactive sizing agents known in theart. Suitably the sizing agent is selected from the group consisting ofhydrophobic ketene dimers, ketene multimers, acid anhydrides, organicisocyanates, carbamoyl chlorides and mixtures thereof, preferably ketenedimers and acid anhydrides, most preferably ketene dimers. Suitableketene dimers have the general formula (I) below, wherein R¹ and R²represent saturated or unsaturated hydrocarbon groups, usually saturatedhydrocarbons, the hydrocarbon groups suitably having from 8 to 36 carbonatoms, usually being straight or branched chain alkyl groups having 12to 20 carbon atoms, such as hexadecyl and octadecyl groups. Suitableacid anhydrides can be characterized by the general formula (II) below,wherein R³ and R⁴ can be identical or different and represent saturatedor unsaturated hydrocarbon groups suitably containing from 8 to 30carbon atoms, or R³ and R⁴ together with the —C—O—C— moiety can form a 5to 6 membered ring, optionally being further substituted withhydrocarbon groups containing up to 30 carbon atoms. Examples of acidanhydrides which are used commercially include alkyl and alkenylsuccinic anhydrides and particularly isoocta-decenyl succinic anhydride.

Suitable ketene dimers, acid anhydrides and organic isocyanates includethe compounds disclosed in U.S. Pat. No. 4,522,686, which is herebyincorporated herein by reference. Examples of suitable carbamoylchlorides include those disclosed in U.S. Pat. No. 3,887,427 which isalso incorporated herein by reference.

In addition to the cellulose-reactive sizing agent, the size dispersionsmay also contain a non-cellulose-reactive sizing agent. Examples ofsuitable sizing agents of this type include rosins, e.g. fortifiedand/or esterified rosin, waxes, fatty acid and resin acid derivatives,e.g. fatty amides and fatty esters, e.g. glycerol triesters of naturalfatty acids.

The cationic compound comprised in the present invention preferablycontains one or more cationic groups of the same or different types andinclude cationic compounds having one cationic group and cationiccompounds having two or more cationic groups, i.e. cationicpolyelectrolytes. Examples of suitable cationic groups include sulfoniumgroups, phosphonium groups, acid addition salts of primary, secondaryand tertiary amines or amino groups and quaternary ammonium groups, forexample where the nitrogen has been quaternized with methyl chloride,dimethyl sulfate or benzyl chloride, preferably acid addition salts ofamines/amino groups and quaternary ammonium groups. Cationicpolyelectrolytes can have a degree of substitution varying over a widerange; the degree of cationic substitution (DS_(C)) can be from 0.01 to1.0, suitably from 0.1 to 0.8 and preferably from 0.2 to 0.6.

Suitable cationic organic compounds for use in this invention includecationic compounds capable of functioning as a surfactant and/ordispersing agent. Preferably the cationic compound is a surfactant. Thecationic surfactant can be selected from primary, secondary, tertiary,and quaternary ammonium compounds containing at least one hydrocarbongroup with from 9 to 30 carbon atoms. Further preferred cationicsurfactants include compounds having the general formula R₄N⁺X⁻, whereineach R group is independently selected from (i) hydrogen; (ii)hydrocarbon groups, suitably aliphatic and preferably alkyl groups,having from 1 to about 30 carbon atoms, preferably from 1 to 22 carbonatoms; and (iii) hydrocarbon groups, suitably aliphatic and preferablyalkyl groups, having up to about 30 carbon atoms, preferably from 4 to22 carbon atoms, and being interrupted by one or more heteroatoms, e.g.oxygen or nitrogen, and/or groups containing a heteroatom, e.g. carbonyland acyloxy groups; where at least one, suitably at least three andpreferably all of said R groups contain carbon atoms; suitably at leastone and preferably at least two of said R groups containing at least 7carbon atoms, preferably at least 9 carbon atoms and most preferably atleast 12 carbon atoms; and wherein X⁻is a counter-ion, typically ahalide like chloride, or a group present in the counter-ion compound ofthe dispersant, e.g. where the surfactant is a protonated amine of theformula R₃N wherein R and N are as defined above. Examples of suitablesurfactants include dioctyl-dimethylammonium chloride,didecyldimethylammonium chloride, dicoco-dimethylammonium chloride,cocobenzyldimethylammonium chloride,coco(fractionated)-benzyldimethylammonium chloride, octadecyltrimethylammonium chloride, dioctadecyl dimethylammonium chloride,dihexadecyl dimethylammonium chloride, di(hydrogenatedtallow)dimethylammonium chloride, di(hydrogenatedtallow)benzylmethylammonium chloride, (hydrogenatedtallow)benzyldimethylammonium chloride, dioleyldimethyl-ammoniumchloride, and di(ethylene hexadecanecarboxylate)dimethylammoniumchloride. Particularly preferred cationic surfactants thus include thosecontaining at least one hydrocarbon group with from 9 to 30 carbon atomsand notably quaternary ammonium compounds.

Further preferred cationic surfactants include quaternary di- andpolyammonium compounds containing at least one hydrocarbon group,suitably aliphatic and preferably alkyl, with from 9 to 30 carbon atoms,preferably from 12 to 22 carbon atoms. Examples of suitable surfactantsof this type includeN-octadecyl-N-dimethyl-N′-trimethyl-propylene-diammonium dichloride.

Preferred cationic polyelectrolytes used in the present inventionfurther include low molecular weight cationic organic polymers,optionally degraded, e.g. those derived from polysaccharides likestarches and guar gums, cationic condensation products like cationicpolyurethanes, polyamideamines, e.g. polyamideamine-epichlorohydrincopolymers, polyamines, e.g. dimethylamine-epichlorohydrin copolymers,dimethylamine-ethylenediamine-epichlorohydrin copolymers,ammonia-ethylenendichloride copolymers, vinyl addition polymers formedfrom monomers with cationic groups, e.g. homopolymers and copolymers ofdiallyldimethylammonium chloride, dialkylaminoalkyl acrylates,methacrylates and acrylamides (e.g. dimethylaminoethyl acrylates andmethacrylates) which usually are present as acid addition salts orquaternary ammonium salts, optionally copolymerized with non-ionicmonomers including acrylamide, alkyl acrylates, styrene andacrylonitrile and derivatives of such monomers, vinyl esters, and thelike.

The molecular weight of the cationic organic compound generally are upto about 10,000, usually up to about 5,000, suitably up to about 3,000and preferably up to about 800. The molecular weight is usually at leastabout 200. Suitable cationic surfactants may have a molecular weight upto about 3,000 and preferred cationic surfactants have a molecularweight between about 200 and about 800.

Suitable non-ionic compounds for use in this invention include non-ioniccompounds functioning as surfactants and/or dispersing agents. Thenon-ionic compounds are usually polyalkylene oxide ethers orpolyalkylene oxide esters or mixtures thereof. Suitably, the non-ioniccompounds comprise a polyalkylene oxide moiety and an aliphatic moiety.The polyalkylene oxide moiety of the non-ionic compound can contain oneor different alkylene oxide unit. Suitably the non-ionic compoundcomprise at least 3 alkylene oxide units, preferably from 4 up to 100and more preferably from 5 up to 60 alkylene oxide units and mostpreferably from 5 up to 50 alkylene oxide units. Common alkylene oxideunits are ethylene oxide or propylene oxide. The aliphatic moiety of thenon-ionic compound, usually linked by an ester or an ether group to thepolyalkylene oxide moiety is suitably branched, linear and or cyclic.Usually, the aliphatic moiety is an alkyl or an alkenyl group containingat least 4 carbon atoms. Suitable non-ionic compound are ethoxylatedfatty ethers, ethoxylated fatty esters or ethoxylated nonylphenols orsilicone glycol polymers are examples of compounds which can be used inthis invention. Further examples of preferred non-ionic compound used inthe present invention are disclosed in Ullman's Encyclopaedia ofIndustrial Chemistry, 5 Edition, Voume A25, pages 783-793; Kirk OthmerEncyclopaedia of Chemical Technology, 4 Edition, Volume 23, pages506-523 and Handbook of industrial surfactants, second edition 1997,Gower Publishing Limited, which are all hereby incorporated byreference.

The amount of cationic and non-ionic compounds present in thesubstantially water-free composition and aqueous composition accordingto the invention can be varied over a broad range depending on, amongother things, type and charge density of the cationic and non-ionicmaterials, type of sizing agent, desired cationicity and solids contentof the resulting dispersion. In the substantially water-free compositionand aqueous composition the cationic compound can be present in anamount of up to 100% by weight, usually from 0.1 to 20% by weight,suitably from 1 to 10% by weight and preferably from 2 to 7% by weight,based on the sizing agent, and the non-ionic compound can be present inan amount of up to 100% by weight, usually from 0.1 to 20% by weight,suitably from 0.2 to 10% by weight and preferably from 0.3 to 6% byweight, based on the sizing agent.

According to the present invention the sizing composition issubstantially water-free. By substantially water-free is usually meantthat a small amount of water can be present; the water content can befrom 0 up to 10% by weight, suitably less than 5% by weight andpreferably less than 2%. Most preferably the composition is free fromwater.

According to a preferred embodiment of the present invention thesubstantially water-free composition is essentially free from rosinsand/or derivatives of rosins. By essentially free is meant that theaqueous composition obtained after dispersing the essentially water-freecomposition contains less than 5 weight % of rosins and/or derivativesof rosins, suitably less than 2 weight %. More preferably, thesubstantially water-free composition is free from rosins and/orderivatives of rosins.

The composition preferably contains the cellulose-reactive sizing agentin a predominant amount, based on weight, suitably at least 50% byweight, and suitably the composition has sizing agent content within therange of from 80 to 99.8% by weight and preferably from 90 to 99.7% byweight.

According to the present invention an aqueous composition of acellulose-reactive sizing agent is provided comprising a cationiccompound with a molecular weight up to 10,000 and a non-ionic compound.The aqueous compositions of the invention can be prepared in high solidscontents and yet exhibit very good stability on storage and lowviscosity. Accordingly, this invention provides size dispersions withgood and/or improved storage stability, higher solids content and/orlower viscosity. A further benefit observed with the present aqueouscomposition is very good and/or improved dilute stability which meanslow aggregation of the particles or droplets of sizing agent, therebyforming lower levels of bigger aggregates having lower sizingefficiency, as well as low deposition of the hydrophobic sizing agent onthe paper machine and less wire contamination, thereby reducing the needfor maintenance of the paper machine. The present aqueous compositionsgenerally can have sizing agent contents of from about 1 to about 60%.Compositions containing a ketene dimer sizing agent according to theinvention may have ketene dimer contents within the range of from 5 toabout 50% by weight and preferably from about 10 to about 35% by weight.Dispersions, or emulsions, containing an acid anhydride sizing agentaccording to the invention may have acid anhydride contents within therange from 0.1 to about 30% by weight and usually from about 1 to about20% by weight.

It has further surprisingly been found that the essentially water-freecomposition of a cellulose-reactive sizing agent according to thepresent invention easily can be homogenised in the presence of anaqueous phase. Less energy and lower shear forces are required in thisprocess compared to processes for preparing conventional dispersions andhereby simplified equipment can be employed. The substantiallywater-free composition according to the invention can be produced bymelting the sizing agent and adding the non-ionic compound and thecationic compound thereto. According to yet another preferredembodiment, the substantially water-free composition can be produced bymelting the sizing agent and adding the cationic compound. The so formedcomposition is then suitably emulsified in the presence o fan aqueousphase comprising the non-ionic compound. After cooling the melt solidpellets are formed. The aqueous composition or dispersion of a sizingagent can be obtained by heating a water phase suitably up to atemperature where the sizing agent is present in liquid form, preferablyfrom about 20° C. up to 95° C. Accordingly, another preferred embodimentof the present invention refers to a method for the preparation of anaqueous dispersion of a cellulose-reactive sizing agent where thesubstantially water-free composition is emulsified in the presence of anaqueous phase. Yet another preferred embodiment of the present inventionis a method for the preparation of an aqueous dispersion of acellulose-reactive sizing agent where a substantially water-free sizingcomposition comprising a cellulose-reactive sizing agent and a cationiccompound with a molecular weight of up to 10,000 is emulsified in thepresence of an aqueous phase containing a non-ionic compound. Thesubstantially water-free composition of the invention is suitably addedto the aqueous phase at an amount to give an aqueous composition ordispersion with a sizing agent content within the range of from about0.1 up to about 90% by weight preferably from about 0.1 up to about 50%by weight. After the addition of the composition to the aqueous phasethe formed aqueous composition preferably is emulsified, suitably underpressure, whereby a dispersion is formed. The size composition ispreferably emulsified at the location of intended use, or elsewhere.This method is especially attractive when preparing emulsions of ketenedimers. The provision of a storage-stable substantially water-free sizecomposition thus offers considerable economic and technical benefits.The substantially water-free sizing composition is suitably formulatedas pellets which can have various shapes.

The components that are present in the composition according to theinvention, i.e., the cellulose-reactive sizing agent, the cationiccompound and the non-ionic compound, preferably are defined as above.

The compositions and dispersions according to the invention can be usedin conventional manner in the production of paper using any type ofcellulosic fibres and they can be used both for surface sizing andinternal or stock sizing. The term “paper”, as used herein, is meant toinclude not only paper but all types of cellulose-based products insheet and web form, including, for example, board and paperboard. Thestock contains cellulosic fibres, optionally in combination with mineralfillers, and usually the content of cellulosic fibres is at least 50% byweight, based on dry stock. Examples of mineral fillers of conventionaltypes include kaolin, china clay, titanium dioxide, gypsum, talc andnatural and synthetic calcium carbonates such as chalk, ground marbleand precipitated calcium carbonate. The present invention also relatesto a method for the production of paper in which an aqueous dispersion,as defined above, is used as a surface or stock size. Suitably theamount of cellulose-reactive sizing agent either added to the stockcontaining cellulosic fibres, and optional fillers, to be drained on awire to form paper, or applied on the paper surface as a surface size,usually at the size press, is from 0.01 to 1.0% by weight, based on thedry weight of cellulosic fibres and optional fillers, preferably from0.05 to 0.5% by weight, where the dosage is mainly dependent on thequality of the pulp or paper to be sized, the cellulose-reactive sizingagent used and the level of sizing desired.

Chemicals conventionally added to the stock in papermaking such asretention aids, aluminium compounds, dyes, wet-strength resins, opticalbrightening agents, etc., can of course be used in conjunction with thepresent compositions. Examples of aluminium compounds include alum,aluminates and polyaluminium compounds, e.g. polyaluminium chlorides andsulphates. Examples of suitable retention aids include cationicpolymers, anionic inorganic materials in combination with organicpolymers, e.g. bentonite in combination with cationic polymers,silica-based sols in combination with cationic polymers or cationic andanionic polymers. Particularly good stock sizing can be obtained whenusing the aqueous compositions or dispersions of the invention incombination with retention aids comprising cationic polymers. Suitablecationic polymers include cationic starch, guar gum, acrylate-based andacrylamide-based polymers, polyethyleneimine, dicyandiamide-formaldehyderesins, polyamines, polyamidoamines and poly(diallyldimethylammonium-chloride) and combinations thereof. Cationic starch andcationic acrylamide-based polymers are preferably used, either alone orin combination with each other or with other materials. In a preferredembodiment of the invention, the dispersions are used in combinationwith a retention system comprising at least one cationic polymer andanionic silica-based particles. The present aqueous compositions ordispersions can be added before, between, after or simultaneously withthe addition of the cationic polymer or polymers. It is also possible topre-mix the size dispersion obtained by homogenisation of theessentially water-free composition with a retention aid, e.g. a cationicpolymer like cationic starch or a cationic acrylamide-based polymer, oran anionic silica-based material, prior to introducing the mixture thusobtained into the stock. Accordingly, the aqueous composition ordispersion can be prepared just prior to introducing it into the stockby emulsifying a substantially water-free size composition according tothe invention with an aqueous solution.

The invention is further illustrated in the following examples, which,however, are not intended to limit the same. Parts and % relate to partsby weight and % by weight, respectively, unless otherwise stated.

EXAMPLE 1

Sizing effiency of an aqueous size composition according to theinvention was evaluated in this example. A dispersion of AKD wasprepared by melting 94,5 grams of AKD with 4.0 grams of cationic amine(di(hydrogenated tallow)dimethylammonium chloride, Querton 442 AkzoNobel trade name) and 1.5 grams of a non-ionic compound (polyethyleneoxide alkyl having 7 ethylene oxide units and alkyl moiety containing 11carbon atoms, Berocell 537). The melt was solidified to form pellets. 50grams of these pellets were added to water at 60° C. and melted. AnUltra Turrax mixer at 15,000 rpm was used for 60 seconds to prepare thedispersion. Paper sheets were prepared according to the standard methodSCAN-C23X for laboratory scale. The papermaking stock used contained 80%of bleached birch and 20% chalk to which 0.3 g/l Na₂SO₄*10 H₂O wasadded. Stock consistency was 0.5% and pH 8.0. The size dispersion wasused in conjunction with a commercial retention and dewatering system,Compozil™, comprising cationic starch and an anionic aluminium-modifiedsilica sol which were added to the stock separately; the cationic starchwas added in an amount of 7 kg/ton, based on dry stock, and the silicasol was added in an amount of 0.8 kg/ton calculated as SiO₂ and based ondry stock. Cobb value, measured according to TAPPI standard T441 OS-63,obtained in the tests was 17 g/m2 at an addition level of AKD of 0.6kg/ton calculated on dry stock. This Cobb value indicates a good sizingof the paper using the sizing compositions according to this invention.

EXAMPLE 1

Ease of manufacture of dispersions according to the invention wasevaluated by preparing aqueous dispersions from substantially water-freesizing compositons. Dispersions of the invention were prepared by a)emulsifying substantially water-free compositions of AKD (alkyl ketenedimer) containing a cationic amine (di(hydrogenatedtallow)dimethylammonium chloride, Querton 442, Akzo Nobel) and varyingamounts of a non-ionic compound (polyethylene oxide alkyl having 7ethylene oxide units and alkyl moiety containing 11 carbon atoms,Berocell 537) (tests C1-C3) b) emulsifying substantionally water-freecompositions of AKD containing the cationic amine whereby differentamounts of non-ionic compound were added to the aqueous phase beforeemulsification. Reference substantially water-free sizing compositionsaccording to prior art was evaluated comprising AKD, and cationic amine(A and B). The AKD-wax was for the invention mixed with 2,4 weight %based on AKD of the cationic amine and 1, 2 and 3 weight % based on AKDof the non-ionic compound. In tests C1-C3 the non-ionic compound wascontained in the substantially water-free sizing composition. In testsD1-D3 the non-ionic compound was present in the aqueous phase. In test Ea substantially water-free sizing composition was evaluated containingAKD, 0,9 weight % based on AKD of a non-ionic compound containing about56 propylene oxide and ethylene oxide units (Pluronic PE 10500) and 0,4weight % based on AKD of Polydadmac FL45C with a molecular weight ofabout 200,000 to 500,000. The composition was subsequently dispersed inan aqueous phase.

The substantially water-free AKD compositions were made by melting theAKD adding the cationic amine and the non-ionic compound or adding onlythe cationic amine and thereafter cooling the melt and forming solidpellets. The reference compositions according to the prior art were madeof pellets containing the cationic amine and AKD which subsequently wereemulsified in the presence of an aqueous phase containing sodiumnaphtalene sulphonate (A) or which were emulsified in the presence of anaqueous phase containing no sodium naphtalene sulphonate (B).

The preparation of the dispersions was made by heating the aqueous phaseto about 70° C. and adding to the aqueous phase substantially water-freeAKD compositions in form of pellets. After the addition a mixer, UltraTurrax with a speed of 15000 rpm, was used for thehomogenisation/emulsification. Mixing times were varied between 5 to 180seconds. The particle size was measured by a Malvern Mastersizer.

TABLE 1 Dispersing times A B C1 C2 C3 D1 D2 D3 E  5 15 >100 8.6 7.3 7.37.7 8.6 5.7 4.4 15 6.8 7.5 5.6 5.7 4.8 5.3 4.9 4.3 5.6 30 4.8 5.2 4.34.1 2.3 4.6 3.9 3.2 3.3 60 3.7 3.5 3.0 1.9 1.2 2.9 2.5 1.4 4.1 180  1.10.8 1.0 0.9 0.7 1.3 0.8 0.7 4.5

Particle size is in microns for 50% volume.

Table 1 demonstrates that by adding a non-ionic surfactant to theaqueous phase or to the AKD pellets, a reduction in the particle size isachieved much faster thus reducing the needed time and energy forforming a dispersion. For E a fast decrease in particle size wasachieved, however, the particles were never smaller than 3,3 micronswhich is not acceptable.

What is claimed is:
 1. A substantially water-free composition of acellulose-reactive sizing agent, the cellulose-reactive sizing agentbeing a ketene dimer sizing agent, said composition further comprising acationic surfactant having a molecular weight up to about 10,000selected from primary, secondary, tertiary or quaternary ammoniumcompounds containing at least one hydrocarbon group with from 9 up to 30carbon atoms, and a non-ionic compound comprising a polyalkylene oxidemoiety and an aliphatic moiety, said composition being essentially freefrom rosins and derivatives of rosins.
 2. The substantially water-freecomposition according to claim 1, wherein the cationic surfactant ispresent in an amount of from 0.1 to 20% by weight, based on the sizingagent, and the non-ionic compound is present in an amount of from 0.1 to20% by weight, based on the sizing agent.
 3. The substantiallywater-free composition according to claim 1, wherein the cationicsurfactant has a molar weight of from 200 to
 800. 4. The substantiallywater-free composition according to claim 1, wherein the cationicsurfactant is selected from dioctyldimethylammonium chloride,didecyldimethylammonium chloride, dicocodimethylammonium chloride,cocobenzyldimethylammonium chloride,coco(fractionated)benzyldimethylammonium chloride, octadecyltrimethylammonium chloride, dioctadecyl dimethylammonium chloride,dihexadecyl dimethylammonium chloride, di(hydrogenatedtallow)dimethylammonium chloride, di(hydrogenatedtallow)benzylmethylammonium chloride, (hydrogenatedtallow)benzyldimethylammonium chloride, dioleyldimethylammoniumchloride, di(ethylene hexadecanecarboxylate)dimethylammonium chloride,and N-octadecyl-N-dimethyl-N′-trimethyl-propylene-diammonium dichloride.5. A method for the preparation of an aqueous dispersion of acellulose-reactive sizing agent comprising dispersing in water thecomposition according to claim
 1. 6. A method for the preparation of anaqueous dispersion of a cellulose-reactive sizing agent characterised inthat a substantially water-free sizing composition comprising acellulose-reactive sizing agent and a cationic compound with a molecularweight of up to 10,000 is emulsified in the presence of an aqueous phasecontaining a non-ionic compound.
 7. A method for the production of papercomprising adding a stock sizing agent or surface sizing agent whichincludes a composition according to claim
 1. 8. A process for theproduction of paper comprising adding the substantially water-freecomposition of claim 1 to a stock containing cellulosic fibres andoptional fillers, and dewatering the stock on a wire to obtain paper andwhite water.
 9. The substantially water-free composition according toclaim 1, wherein the ketene dimer sizing agent is present in an amountof at least 50% by weight.
 10. The substantially water-free compositionaccording to claim 1, wherein the cationic surfactant is selected fromsurfactants having the general formula R₄N⁺X⁻, wherein each R group isindependently selected from (i) hydrogen; (ii) hydrocarbon groups havingfrom 1 to about 30 carbon atoms; and (iii) hydrocarbon groups having upto about 30 carbon atoms being interrupted by one or more hetero atomsand/or groups containing a hetero atom, wherein at least one of the Rgroups contains 9-30 carbon atoms.
 11. The substantially water-freecomposition according to claim 1, wherein the non-ionic compoundcomprises a polyalkylene oxide moiety having from 5 up to 60 alkyleneoxide units and an aliphatic moiety linked by an ether or ester group tothe polyalkylene oxide moiety, wherein the aliphatic moiety is an alkylor alkenyl group comprising at least 4 carbon atoms.
 12. A method forthe preparation of an aqueous dispersion from the substantiallywater-free composition of claim 1, wherein the substantially water-freecomposition is emulsified in the presence of an aqueous phase.